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Commit cb723180 authored by Mimi Zohar's avatar Mimi Zohar
Browse files

evm: add evm_inode_init_security to initialize new files 



Initialize 'security.evm' for new files.

Changelog v7:
- renamed evm_inode_post_init_security to evm_inode_init_security
- moved struct xattr definition to earlier patch
- allocate xattr name
Changelog v6:
- Use 'struct evm_ima_xattr_data'

Signed-off-by: default avatarMimi Zohar <zohar@us.ibm.com>
parent 975d2943

include/linux/evm.h

+11 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#define _LINUX_EVM_H



#include <linux/integrity.h>

#include <linux/xattr.h>



#ifdef CONFIG_EVM

extern enum integrity_status evm_verifyxattr(struct dentry *dentry,
@@ -25,6 +26,9 @@ extern void evm_inode_post_setxattr(struct dentry *dentry, 
extern int evm_inode_removexattr(struct dentry *dentry, const char *xattr_name);

extern void evm_inode_post_removexattr(struct dentry *dentry,

				       const char *xattr_name);

extern int evm_inode_init_security(struct inode *inode,

				   const struct xattr *xattr_array,

				   struct xattr *evm);

#else

#ifdef CONFIG_INTEGRITY

static inline enum integrity_status evm_verifyxattr(struct dentry *dentry,
@@ -67,5 +71,12 @@ static inline void evm_inode_post_removexattr(struct dentry *dentry, 
	return;

}



static inline int evm_inode_init_security(struct inode *inode,

					  const struct xattr *xattr_array,

					  struct xattr *evm)

{

	return -EOPNOTSUPP;

}



#endif /* CONFIG_EVM_H */

#endif /* LINUX_EVM_H */

security/integrity/evm/evm.h

+3 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
 * File: evm.h

 *

 */

#include <linux/xattr.h>

#include <linux/security.h>

#include "../integrity.h"
@@ -29,5 +30,7 @@ extern int evm_update_evmxattr(struct dentry *dentry, 
extern int evm_calc_hmac(struct dentry *dentry, const char *req_xattr_name,

			 const char *req_xattr_value,

			 size_t req_xattr_value_len, char *digest);

extern int evm_init_hmac(struct inode *inode, const struct xattr *xattr,

			 char *hmac_val);

extern int evm_init_secfs(void);

extern void evm_cleanup_secfs(void);

security/integrity/evm/evm_crypto.c

+20 −0
Original line number Diff line number Diff line
@@ -157,6 +157,26 @@ int evm_update_evmxattr(struct dentry *dentry, const char *xattr_name, 
	return rc;

}



int evm_init_hmac(struct inode *inode, const struct xattr *lsm_xattr,

		  char *hmac_val)

{

	struct hash_desc desc;

	struct scatterlist sg[1];

	int error;



	error = init_desc(&desc);

	if (error != 0) {

		printk(KERN_INFO "init_desc failed\n");

		return error;

	}



	sg_init_one(sg, lsm_xattr->value, lsm_xattr->value_len);

	crypto_hash_update(&desc, sg, lsm_xattr->value_len);

	hmac_add_misc(&desc, inode, hmac_val);

	crypto_free_hash(desc.tfm);

	return 0;

}



/*

 * Get the key from the TPM for the SHA1-HMAC

 */

security/integrity/evm/evm_main.c

+38 −0
Original line number Diff line number Diff line
@@ -98,6 +98,12 @@ static int evm_protected_xattr(const char *req_xattr_name) 
			found = 1;

			break;

		}

		if (strncmp(req_xattr_name,

			    *xattrname + XATTR_SECURITY_PREFIX_LEN,

			    strlen(req_xattr_name)) == 0) {

			found = 1;

			break;

		}

	}

	return found;

}
@@ -245,6 +251,38 @@ void evm_inode_post_setattr(struct dentry *dentry, int ia_valid) 
	return;

}



/*

 * evm_inode_init_security - initializes security.evm

 */

int evm_inode_init_security(struct inode *inode,

				 const struct xattr *lsm_xattr,

				 struct xattr *evm_xattr)

{

	struct evm_ima_xattr_data *xattr_data;

	int rc;



	if (!evm_initialized || !evm_protected_xattr(lsm_xattr->name))

		return -EOPNOTSUPP;



	xattr_data = kzalloc(sizeof(*xattr_data), GFP_NOFS);

	if (!xattr_data)

		return -ENOMEM;



	xattr_data->type = EVM_XATTR_HMAC;

	rc = evm_init_hmac(inode, lsm_xattr, xattr_data->digest);

	if (rc < 0)

		goto out;



	evm_xattr->value = xattr_data;

	evm_xattr->value_len = sizeof(*xattr_data);

	evm_xattr->name = kstrdup(XATTR_EVM_SUFFIX, GFP_NOFS);

	return 0;

out:

	kfree(xattr_data);

	return rc;

}

EXPORT_SYMBOL_GPL(evm_inode_init_security);



static struct crypto_hash *tfm_hmac;	/* preload crypto alg */

static int __init init_evm(void)

{